Clostridium difficile-associated disease (CDAD) is a major problem for hospitalized patients recieving antibiotics or antineoplastic agents. Current labotatory methods for diagnosing CDAD include culture and assays for detection of the toxins produced by the organism or a cell-associated antigen. PCR assays for the diagnosis of CDAD have been reported in the liturature, but these reports are limited in scope and many of the primer pairs used are inefficient or amplify inappropriate portions of the C. difficile genome. We have selected 5 primer pairs specific for the two toxin genes of C. difficile. We are in the process of selecting the two primer pairs that are the most efficient in amplifying their targets. We will then develop a realtime PCR using the Light Cycler and will use this assay to evaluate the utility of PCR for the diagnosis of CDAD using stool specimens.